Chromosome 4q includes one of the most frequent chromosomal regions exhibiting high frequency of allelic losses in hepatocellular carcinoma (HCC),1-5 with commonly deleted regions at 4q21-22, 4q26-q27, and 4q35.6,7 Chromosomal alterations at 4q are of great interest because it is a unique trait for HCC,8 and 4q contains genes expressed predominantly in the liver. Introduction of human chromosome 4 suppressed the tumorigenicity of teratocarcinoma cell PA-1 in nude mice.9 Studies have shown that 4q alterations are more frequently associated with advanced stage and poor differentiation.3,7,10,11 These findings indicate the existence of tumor suppressor gene(s) at this region. But, it was also shown that the loss of 4q in HCC did not correlate with tumor differentiation and vascular invasion,12 and the frequent loss of 4q was observed in the preneoplastic liver cell dysplasia.13 The reasons for these discrepancies remain to be elucidated.